This invention relates to storage batteries in general and more particularly a method and apparatus for determining the maintenance and charge condition of lead storage batteries.
One common testing method for checking the condition, for instance, of a motor vehicle battery, such as is practiced at any filling station, consists of measuring the no-load voltage of the battery, followed if necessary by measuring its terminal voltage under load. If the measurement of the no-load voltage shows that the battery is insufficiently charged, no further information can be obtained regarding the condition of the battery by measuring the terminal voltage under load. The battery must first be recharged.
A measurement of the acid density, which can also be made, can furnish further indications of the condition of the battery, but such a measurement with a hydrometer is difficult to incorporate into the computer diagnosis now performed by many motor vehicle garages.